Claude Opus 5.5 vs GPT-5.1-Codex-Max

Price, context window & benchmark comparison

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Claude Opus 5.5

Anthropic
$4.00 / $20.00
Input / Output · per 1M tokens
VS
O

GPT-5.1-Codex-Max

OpenAI
$1.25 / $10.00
Input / Output · per 1M tokens
Compare different models
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Verdict: GPT-5.1-Codex-Max is 2.3× cheaper than Claude Opus 5.5 on a typical 3:1 input/output mix. Claude Opus 5.5 has the larger context window (1M vs 400K).
Claude Opus 5.5GPT-5.1-Codex-Max
Input price / 1M$4.00$1.25
Output price / 1M$20.00$10.00
Blended price (3:1)$8.00$3.44
Cached input / 1M$0.20$0.13
Context window1M400K
Max output128K128K
Intelligence index57.6
Coding index
Providers11
Best provider uptime (30m)100.0%
Vision inputYesYes
ReasoningYesYes
Tool callingYesYes
Released2026-09-222025-12-04
Retirement

Cost calculator

FAQ

Which is cheaper, Claude Opus 5.5 or GPT-5.1-Codex-Max?

GPT-5.1-Codex-Max is 2.3× cheaper than Claude Opus 5.5 on a typical 3:1 input/output mix.

Claude Opus 5.5 vs GPT-5.1-Codex-Max: which has a bigger context window?

Claude Opus 5.5: 1,000,000 tokens. GPT-5.1-Codex-Max: 400,000 tokens.

How much would 1 million requests cost?

At 2,000 input + 500 output tokens per request: Claude Opus 5.5 ≈ $18,000, GPT-5.1-Codex-Max ≈ $7,500.

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